Hydrophilic non-porous organic polymers, such as polyurethanes, transport water vapor molecules through them by a molecular transport mechanism. Thus, these polymers "breathe", i.e., allow water vapor, as in perspiration, to pass through them even though they are not porous, i.e., do not contain voids running from one side to the other. Because they are non-porous, they are liquid water impervious and air-impermeable (windproof and contamination resistant).
These qualities make them useful as continuous coatings on fabrics, such as cotton, wool, nylon, polyester or the like, that are used in garment constructions. Alternatively, continuous films of such "breathable" polymers are adhesively bonded to these fabrics to create fabric laminates useful in making clothing articles. These fabric laminates "breathe" thereby keeping the wearer comfortable while providing protection from the environment by keeping out rain, wind, snow, viruses, particulates, etc.
It is well known in the art that breathable fabric laminates are created by bonding a continuous film of a hydrophilic polymer to a fabric substrate by using a hydrophobic adhesive deposited in a discontinuous, non-interconnected pattern. U.S. Pat. No. 4,935,287 to Johnson and U.S. Pat. No. 4,761,324 to Rautenberg, for example, describe such lamination methods.
It is a common practice to use engraved gravure rolls to deposit such discontinuous, non-interconnected adhesive patterns on a substrate. Details of such patterns can be found in standard books like "Modern Coating and Drying Technology", p. 103, E. D. Cohen and E. B. Gutoff (editors), VCH Publishers, Inc., New York, 1992 and "Handbook of Pressure Sensitive Adhesive Technology", p. 789, D. Satas (editor), Van Nostrand Reinhold, New York, 1989, as well as in U.S. Pat. No. 4,761,324 by Rautenberg. However, no reference was found directed to the use of engraved gravure rolls to deposit discontinuous, but interconnected adhesive pattern to laminate a hydrophilic polymer film to a fabric layer to create a breathable fabric laminate.
A problem with these breathable fabric laminates is their poor durability during washing. Owing to the hydrophilic nature of the breathable polymer film, it is difficult to get the film to remain bonded to the fabric during continuous washing. This is a serious deficiency in these laminates as these are used to construct garments that are subjected to laundering.